The　objective　of　this　work　is　to　develop　a　numerical　model　to　stimulate　organic　variation　accurately　in　the　leachate,　to　provide　support　for　landfill　management,　and　to　minimize　the　risks　of　environmental　pollution.　A　mathematical　model　simulating　organic　variation　in　the　leachate　of　bioreactor　landfill　was　presented　and　demonstrated　based　on　mass　balance　of　contaminants　and　degradation　kinetics.　The　model　was　solved　numerically　using　a　fourth-order　Range-Kutta　algorithm　and　the　model　parameters　were　validated　by　monitoring　data.　Efficiency　assessment　and　T　test　were　performed　for　simulating　results,　and　the　efficiency　coefficients　were　respectively　0.7766　and　0.9193　for　column　1　and　column　2.　T　test　result　showed　that　the　simulating　results　and　monitoring　data　have　no　marked　difference.　Given　the　limitations　in　data　capture,　a　sensitivity　analysis　was　performed,　highlighting　the　model＇s　response　to　changes　in　input　variables.　The　sensitivity　index　of　kl　was　more　than　that　of　kls,　and　it　was　the　least　for　ksg.　Moreover,　illustrative　examples　of　the　model＇s　output　are　presented　to　demonstrate　effects　of　data　uncertainty　on　organic　concentration　by　Monte　Carlo　method.　Thus,　the　numerical　model　presented　in　paper　can　stimulate　the　organic　variation　accurately　and　comprehensively　in　the　complexly　changeful　landfill.